Nice catch. I thought it was a bit fast...

Without heavy bits: 1.34 ms 

>perl -le "$t1=time; for (1..$ARGV[0]) { delete $INC{'Carp.pm'}; requi
+re Carp; } $t2=time; print(($t2-$t1)/$ARGV[0])" 100000
0.00134

>perl -le "$t1=time; for (1..$ARGV[0]) { delete $INC{'Carp.pm'}; requi
+re Carp; } $t2=time; print(($t2-$t1)/$ARGV[0])" 100000
0.00134

>perl -le "$t1=time; for (1..$ARGV[0]) { delete $INC{'Carp.pm'}; requi
+re Carp; } $t2=time; print(($t2-$t1)/$ARGV[0])" 100000
0.00134

[download]

With heavy bits: 4.75 ms 

>perl -le "$t1=time; for (1..$ARGV[0]) { delete $INC{'Carp.pm'}; delet
+e $INC{'Carp/Heavy.pm'}; require Carp; require Carp::Heavy; } $t2=tim
+e; print(($t2-$t1)/$ARGV[0])" 100000
0.00475

>perl -le "$t1=time; for (1..$ARGV[0]) { delete $INC{'Carp.pm'}; delet
+e $INC{'Carp/Heavy.pm'}; require Carp; require Carp::Heavy; } $t2=tim
+e; print(($t2-$t1)/$ARGV[0])" 100000
0.00474

[download]

In reply to Re^6: "require Carp" may be hazardous to your code (assume) by ikegami
in thread "require Carp" may be hazardous to your code by Steve_p

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